Saturday, March 7, 2009

Exporting a contest

There is a ARRL SSB contest going on this weekend. I have pretty much grown to hate phone contests. With the expanded phone bands the contest is even crowding out the CW bands. There were contesters down as far as 7050 (I'm sure the PSK boys just LOVE that one), and forget about 160 I heard some joker calling "CQ Contest" on 1808.

Bob N4HY is testing a new image rejection scheme for the PowerSDR software, and he sent out a post wondering how he was going to fill up PowerSDR's passband with enough signals to test his code. I shot him back that there is a contest going on. I guess his antennas are down, or he was not at home, so getting on the air for him was not an option.

Then something really weird happened, he asked me to export him some of the contest. I described the ability to record audio in a previous post. You can record either post processed audio OR you can record preprocessed baseband audio. As you recall I described the F5K basically as a dual conversion receiver. First there is an analogue conversion. In that conversion RF is turned into IQ baseband audio. In the second conversion the baseband audio is digitized and sent into the computer where the second conversion resides in the PowerSDR software. PowerSDR IS the second conversion, it does not just control the radio. IT IS THE RADIO! What this means is, if I present PowerSDR with some baseband audio it will gobble it up and process it just the same as if the first conversion was shooting RF converted to base band into the software. PowerSDR is agnostic. It doesn't care from where it gets its baseband to gobble. VERY COOL.

So I did. I recorded some of the contest. I made 3 files, 2 of 75M and one of 40M, of 192khz wide preprocessed baseband audio, that he could then play back into PowerSDR at his QTH. At 192khz width he has 192khz of the band to tune and stress his software design. He could tune the contest from his chair up there where ever in the heck he is living these days (Bob gets around). In fact I can sit here and relive great contest moments from last night's contest as well. I recorded the PS0F pileup on 75 as one of my offerings, so this morning as I sip my freshly made latte, I could go back and relive that din of screaming maniacs calling the PS0. NOT!!!!

Bob will get to do his software development and listen to a band full of strong signal without an antenna. Actually he can do his development even without the hardware part of the receiver... WAIT A MINUTE.....

What if I had a first conversion part of the radio that was strapped to a brace of really good DX-ing antennas, and that receiver was streaming the baseband audio to Bob!!!!! Why he could tune the streaming contest from any easy chair with an internet connection!!! WAIT A MINUTE....

What if I had base band audio streaming to me from a dozen receivers all over the world!!! I could sit and TUNE the contest from a dozen different locations and sip my latte in my slippers (actually I don't wear slippers, I hate slippers, but I DO love latte). I wonder if there are any YOUTHS who are headed to engineering school that might find such an idea enticing. Why I bet there are some YOUTHS scattered across universities across the world who could get really jazzed about an idea like this. There may even be a few hams who can get jazzed about an idea like this. If I was in the contest I would probably have to run assisted, BUT WHAT AN ASSIST!!

Aside: This assist thing really gets me. People spend probably north of a million dollars on these contest efforts building "Man's best contest station" They have hoards of people working on these stations building them and keeping them running. People are assigned titles for specific tasks like "chief of towers" and even are assigned staff!!! How is that not ASSISTED? What a load.

Just something to think about while all the screaming mimi's scream "CQ MIMI, CQ MIMI" up on 20M, or you can just go back to your QST and read about how to build yet another 2M vertical.... lemme see get a 19 3/8 piece of #12, cut it a little long so you can clip some off....

Call to arms

Hear Ye Hear Ye

If you're interested in writing something interesting for this blog regarding your SDR experience let me know. I would like to include things like how your SDR contest station is set up, or your VHF station that uses SDR as the system center, feats of weak signal work or how well the SDR works in various challenging situations. If you are a foreign ham and would like to comment on the growth of SDR in your particular part of the world. Bring it on!

I reserve the right to publish or not, but I'm pretty open to documenting a wide variety of honest experiences from users, for readers to explore. The understanding of SDR in our hobby is so nascent, that I want the reader to be able to see the value of SDR through the eyes of YOUR experience and enthusiasm.